/**
 * @license Copyright (c) 2003-2023, CKSource Holding sp. z o.o. All rights reserved.
 * For licensing, see LICENSE.md or https://ckeditor.com/legal/ckeditor-oss-license
 */
/**
 * @module image/imagecaption/imagecaptionediting
 */
import { Plugin } from 'ckeditor5/src/core';
import { Element, enablePlaceholder } from 'ckeditor5/src/engine';
import { toWidgetEditable } from 'ckeditor5/src/widget';
import ToggleImageCaptionCommand from './toggleimagecaptioncommand';
import ImageUtils from '../imageutils';
import ImageCaptionUtils from './imagecaptionutils';
/**
 * The image caption engine plugin. It is responsible for:
 *
 * * registering converters for the caption element,
 * * registering converters for the caption model attribute,
 * * registering the {@link module:image/imagecaption/toggleimagecaptioncommand~ToggleImageCaptionCommand `toggleImageCaption`} command.
 */
export default class ImageCaptionEditing extends Plugin {
    /**
     * @inheritDoc
     */
    static get requires() {
        return [ImageUtils, ImageCaptionUtils];
    }
    /**
     * @inheritDoc
     */
    static get pluginName() {
        return 'ImageCaptionEditing';
    }
    /**
     * @inheritDoc
     */
    constructor(editor) {
        super(editor);
        this._savedCaptionsMap = new WeakMap();
    }
    /**
     * @inheritDoc
     */
    init() {
        const editor = this.editor;
        const schema = editor.model.schema;
        // Schema configuration.
        if (!schema.isRegistered('caption')) {
            schema.register('caption', {
                allowIn: 'imageBlock',
                allowContentOf: '$block',
                isLimit: true
            });
        }
        else {
            schema.extend('caption', {
                allowIn: 'imageBlock'
            });
        }
        editor.commands.add('toggleImageCaption', new ToggleImageCaptionCommand(this.editor));
        this._setupConversion();
        this._setupImageTypeCommandsIntegration();
        this._registerCaptionReconversion();
    }
    /**
     * Configures conversion pipelines to support upcasting and downcasting
     * image captions.
     */
    _setupConversion() {
        const editor = this.editor;
        const view = editor.editing.view;
        const imageUtils = editor.plugins.get('ImageUtils');
        const imageCaptionUtils = editor.plugins.get('ImageCaptionUtils');
        const t = editor.t;
        // View -> model converter for the data pipeline.
        editor.conversion.for('upcast').elementToElement({
            view: element => imageCaptionUtils.matchImageCaptionViewElement(element),
            model: 'caption'
        });
        // Model -> view converter for the data pipeline.
        editor.conversion.for('dataDowncast').elementToElement({
            model: 'caption',
            view: (modelElement, { writer }) => {
                if (!imageUtils.isBlockImage(modelElement.parent)) {
                    return null;
                }
                return writer.createContainerElement('figcaption');
            }
        });
        // Model -> view converter for the editing pipeline.
        editor.conversion.for('editingDowncast').elementToElement({
            model: 'caption',
            view: (modelElement, { writer }) => {
                if (!imageUtils.isBlockImage(modelElement.parent)) {
                    return null;
                }
                const figcaptionElement = writer.createEditableElement('figcaption');
                writer.setCustomProperty('imageCaption', true, figcaptionElement);
                figcaptionElement.placeholder = t('Enter image caption');
                enablePlaceholder({
                    view,
                    element: figcaptionElement,
                    keepOnFocus: true
                });
                const imageAlt = modelElement.parent.getAttribute('alt');
                const label = imageAlt ? t('Caption for image: %0', [imageAlt]) : t('Caption for the image');
                return toWidgetEditable(figcaptionElement, writer, { label });
            }
        });
    }
    /**
     * Integrates with {@link module:image/image/imagetypecommand~ImageTypeCommand image type commands}
     * to make sure the caption is preserved when the type of an image changes so it can be restored
     * in the future if the user decides they want their caption back.
     */
    _setupImageTypeCommandsIntegration() {
        const editor = this.editor;
        const imageUtils = editor.plugins.get('ImageUtils');
        const imageCaptionUtils = editor.plugins.get('ImageCaptionUtils');
        const imageTypeInlineCommand = editor.commands.get('imageTypeInline');
        const imageTypeBlockCommand = editor.commands.get('imageTypeBlock');
        const handleImageTypeChange = evt => {
            // The image type command execution can be unsuccessful.
            if (!evt.return) {
                return;
            }
            const { oldElement, newElement } = evt.return;
            /* istanbul ignore if: paranoid check -- @preserve */
            if (!oldElement) {
                return;
            }
            if (imageUtils.isBlockImage(oldElement)) {
                const oldCaptionElement = imageCaptionUtils.getCaptionFromImageModelElement(oldElement);
                // If the old element was a captioned block image (the caption was visible),
                // simply save it so it can be restored.
                if (oldCaptionElement) {
                    this._saveCaption(newElement, oldCaptionElement);
                    return;
                }
            }
            const savedOldElementCaption = this._getSavedCaption(oldElement);
            // If either:
            //
            // * the block image didn't have a visible caption,
            // * the block image caption was hidden (and already saved),
            // * the inline image was passed
            //
            // just try to "pass" the saved caption from the old image to the new image
            // so it can be retrieved in the future if the user wants it back.
            if (savedOldElementCaption) {
                // Note: Since we're writing to a WeakMap, we don't bother with removing the
                // [ oldElement, savedOldElementCaption ] pair from it.
                this._saveCaption(newElement, savedOldElementCaption);
            }
        };
        // Presence of the commands depends on the Image(Inline|Block)Editing plugins loaded in the editor.
        if (imageTypeInlineCommand) {
            this.listenTo(imageTypeInlineCommand, 'execute', handleImageTypeChange, { priority: 'low' });
        }
        if (imageTypeBlockCommand) {
            this.listenTo(imageTypeBlockCommand, 'execute', handleImageTypeChange, { priority: 'low' });
        }
    }
    /**
     * Returns the saved {@link module:engine/model/element~Element#toJSON JSONified} caption
     * of an image model element.
     *
     * See {@link #_saveCaption}.
     *
     * @internal
     * @param imageModelElement The model element the caption should be returned for.
     * @returns The model caption element or `null` if there is none.
     */
    _getSavedCaption(imageModelElement) {
        const jsonObject = this._savedCaptionsMap.get(imageModelElement);
        return jsonObject ? Element.fromJSON(jsonObject) : null;
    }
    /**
     * Saves a {@link module:engine/model/element~Element#toJSON JSONified} caption for
     * an image element to allow restoring it in the future.
     *
     * A caption is saved every time it gets hidden and/or the type of an image changes. The
     * user should be able to restore it on demand.
     *
     * **Note**: The caption cannot be stored in the image model element attribute because,
     * for instance, when the model state propagates to collaborators, the attribute would get
     * lost (mainly because it does not convert to anything when the caption is hidden) and
     * the states of collaborators' models would de-synchronize causing numerous issues.
     *
     * See {@link #_getSavedCaption}.
     *
     * @internal
     * @param imageModelElement The model element the caption is saved for.
     * @param caption The caption model element to be saved.
     */
    _saveCaption(imageModelElement, caption) {
        this._savedCaptionsMap.set(imageModelElement, caption.toJSON());
    }
    /**
     * Reconverts image caption when image alt attribute changes.
     * The change of alt attribute is reflected in caption's aria-label attribute.
     */
    _registerCaptionReconversion() {
        const editor = this.editor;
        const model = editor.model;
        const imageUtils = editor.plugins.get('ImageUtils');
        const imageCaptionUtils = editor.plugins.get('ImageCaptionUtils');
        model.document.on('change:data', () => {
            const changes = model.document.differ.getChanges();
            for (const change of changes) {
                if (change.attributeKey !== 'alt') {
                    continue;
                }
                const image = change.range.start.nodeAfter;
                if (imageUtils.isBlockImage(image)) {
                    const caption = imageCaptionUtils.getCaptionFromImageModelElement(image);
                    if (!caption) {
                        return;
                    }
                    editor.editing.reconvertItem(caption);
                }
            }
        });
    }
}
